1. Field of the Invention
The present invention relates to compositions of matter. In particular, the present invention relates to filler materials combined with other materials to form compositions. Still more particularly, the present invention relates to filler-based compositions and methods of making such materials for use in the papermaking industry but not limited thereto.
2. Description of the Prior Art
Fillers or pigments are often incorporated into composites, such as paper, paper board or plastics, to improve physical or optical properties and/or to lower the costs of the material. Fillers, and more specifically inorganic pigments, are often added to paper composites to improve surface smoothness, print quality, opacity and brightness and to replace more expensive fiber thereby lowering the cost to manufacture such products. However, it is well known that fillers also reduce the strength of paper and are difficult to retain in the web forming process due to their small physical size relative to common paper making fibers. These limitations often constrain the amount of filler that can be incorporated in paper formulations.
There has been significant effort to produce fillers that impart the desired optical properties in paper and paperboard while minimizing the loss in strength of the paper or paperboard thus produced. One method has been described that involves the manufacture of modified fillers for use in a papermaking process, and modified fillers and paper produced therewith. The method includes making a modified filler by applying starch to a reaction mixture comprising at least of one fatty acid, rosin acid, or ammonium sulfate, and applying a filler to the reaction mixture, thereby forming a modified filler.
Another method provides for the production of filler-containing papers and filler-containing paper products by addition of an aqueous suspension of at least one finely divided polymer-pigment hybrid to a paper stock and drainage of the paper stock to form a sheet of paper. The polymer-pigment hybrid is obtained by milling an aqueous suspension of at least one inorganic pigment in the presence of at least one binder and, if appropriate, by drying the aqueous suspension thus obtainable and re-dispersing the dried polymer-pigment hybrid in water. It is understood that the polymer-pigment hybrids may be used as fillers for the production of filler-containing paper or filler-containing paper products.
While these examples illustrate that modified fillers have been considered for use in papermaking, there is an ongoing need for fillers that can be utilized to produce filled papers and other types of end products, which have optical properties desired for such products while maintaining suitable strength characteristics at an economically viable cost. To date, fillers that have been used in paper and other products generate strength loss and other characteristic retention deficiencies that are simply unsatisfactory and, as a result, fillers and filler-based compositions that may otherwise generate cost savings cannot be implemented in a meaningful way.
What is needed is a filler material or filler-based composition for use in combination with a primary structural material that does not diminish desired optical, physical and processing characteristics of the primary material to a level that makes the end product containing that primary material inadequate for its intended purpose. What is also needed is such a filler material and/or filler-based composition that reduces the overall cost of the end product or that at least does not add to it.